A contractor wiring up a stadium plant room faces the same small decision a hundred times: how to get a temperature off a pipe without breaking into it. Two answers compete. One wraps the pipe with an adjustable strap; the other clamps a metal saddle sized to that exact pipe. They look similar and cost similar. They are not the same buy.

What each one actually is

A pipe-strap sensor holds its sensing tip against the pipe with a flexible, self-locking strap. In an overmoulded design — our TPE-overmoulded construction — the NTC element, its epoxy, and the cable are fused into one sealed body. The MFE1 strap runs about 110 mm long and 7 mm wide and fits pipe up to roughly 35 mm OD; an extension chain doubles that. The locking holes on a 4.5 mm pitch keep it from backing off under thermal cycling. One part number, many diameters — see the MFE1 strap sensor with extension chain.

A metal clamp-on uses a spring clip or worm-drive band sized to one pipe diameter, pressing the element into direct metal contact. Fastest heat transfer, narrowest fit.

Side by side

The detail that decides it: the tip

"Strap vs clamp" is really a question about thermal contact, and a strap sensor can close most of the gap with a metal-capped tip. From the MFE1 datasheet, three tip builds trade response against sealing — and copper carries this because its thermal conductivity (~385 W/m·K) is on the order of a thousand times that of TPE:

The 3-question chooser

1. Is the diameter fixed or varied? Varied → strap. Fixed and known → clamp is viable.
2. How fast must it react? Tight loop or defrost → copper-cap strap or metal clamp. Steady monitoring → bare strap.
3. Is it wet? Washdown, condensation, submersion → sealed strap (IP68), e.g. the IP68 waterproof pipe-clamp sensor.

For threaded boiler and water-pipe points where a fitting already exists, a screw-in part like the G1/2–G1/8 pipe sensor (MFP-7) may beat both. Whatever the style, the reading still lives or dies on mounting — see why your pipe sensor reads 8°F wrong. And if nothing in the catalogue fits, both styles customise; the brief is in Article 10. For the bigger system picture, start at the pillar on stadium pipe sensing.

FAQ

Are pipe surface sensors accurate?

Yes, when mounted with firm contact and insulated over the tip. The dominant error is ambient air reaching the sensor, not the element itself.

What pipe size does a strap sensor fit?

A typical integrated strap fits pipe up to about 35 mm OD; an extension chain roughly doubles the range. Metal clamps are sized to specific bands.

Can I use a strap sensor underwater?

A sealed IP68 overmoulded strap (bare-TPE or copper-sheet tip) is rated for submersion. The copper-tube tip is IP65 — dust- and jet-proof, but not for immersion.